The present invention generally relates to the field of semiconductor manufacturing. More specifically, the present invention relates to a system used in a vertical furnace.
In the vertical furnace, a substantially cylindrical, vertically oriented process tube, made of ceramic material, is supported on a door plate. The process tube defines an opening that is closed by the door plate. In some processes, material may condense on the wall of the process tube. This material may be polyimide by-products that are formed during the annealing of polyimide films on the semiconductor substrate. The material condensed on the wall of the process tube runs downwards on to the sealing surface of the process tube and the door plate. This material is sticky and prevents the easy removal of the door plate from the closable opening.
The material on the sealing surface of the process tube and the door plate causes friction. When the door plate is separated from the process tube, the surfaces rub against each other resulting in the generation of particles. This causes damage to the door plate and the process tube. Replacing the door plate and the process tube is expensive and preventive maintenance at frequent intervals results in a reduction in production.
Accordingly, there is a need for a system that can be used in vertical furnaces for the easy removal of the door plate from the opening. Moreover, the system should prevent the door plate from sticking, to avoid damage to the door plate and the process tube.